Modem communication and networking solutions are increasingly adopting radio as a communications medium. Industry standards such as the IEEE 802.11a/b/g wireless LAN protocols, the ease of deployment, and the demand for mobile access to data and applications have fueled an explosion in the number of wireless Local Area Networks in use both in commercial as well home environments.
An IEEE 802.11a/b/g based wireless LAN may be constructed as shown in FIG. 1, with at least one radio transmitter/receiver hub called an Access Point (AP) 101-102 and one or more wireless devices 103-104, that use these APs 101 and 102 to communicate with each other as shown by radio links 105, or to access a network resource. The APs may be connected to a wired LAN and thus can connect a wireless device 103-104 to a plurality of network resources. It is relatively inexpensive to set up such a wireless LAN, which makes this a popular method for providing network access. It is estimated that there are over 500 million wireless LAN devices in use worldwide today.
However, the use of radio frequency as the medium brings with it a unique set of security related issues. Wireless LANs are inherently different in risk compared to a wired LAN. While in a wired LAN the layers 1 and 2 of the network typically are protected by CAT5 cables in a secured building, in WLANs these layers are exposed because they are implemented using radio waves and therefore cannot be contained by a physical structure such as a building. Unlike wired networks, communication in Wireless LANs is not confined to a physical link such as a CAT5 cable; rather, it is broadcast through the air in multiple directions simultaneously and is therefore visible, and may be intercepted and deciphered. Essentially anyone with an available radio can eavesdrop and interject traffic into a wireless networks communication stream. This use of a non-physical communication link, i.e. radio waves, makes Wireless LANs more vulnerable to security threats than wired networks which use a cable such as a CAT5 cable to propagate data.
FIG. 1 illustrates a typical enterprise Wireless LAN. In IEEE 802.11a/b/g based WLANs, wireless devices are permitted to seek out and try to connect with other wireless devices in their vicinity as shown in Wireless LAN area 106 and to form ad-hoc networks. This uncontrolled association further increases the threat to an enterprise Wireless LAN. For example, an authorized user on the corporate network can innocently connect to a neighbor's network or be maliciously lured to connect to an undesirable or unauthorized wireless device outside of the company premises and thereby compromise the entire corporate network. For reasons such as these, mechanisms to secure Wireless LANs have become an area of great interest and a huge business opportunity.
Two key factors have driven the development of WLAN Security solutions and to a great degree existing industry standards:
1. “Wired network security mindset,” which believes/operates on the assumption that once the access to a network is controlled, the network is safe. If data is encrypted for an added measure, then the result is foolproof security.
2. Failure of solutions developed with this mindset has made vendors more determined to make it succeed—by developing stronger access controls, stronger encryption, and dynamic keys.
The result is a myriad of expensive proprietary solutions that do not address the fundamental risks of using the radio frequency (RF) medium, and which, therefore, do not decrease the threats. Most of these passive solutions are cumbersome to deploy, because they do not take advantage of existing wired network infrastructure and they are economically prohibitive to maintain.
Prior Art
Most existing attempts to provide security for industry standard IEEE 802.11a/b/g Wireless LANs may be categorized as follows:
1. WEP based security solutions. This is the most basic form of security that is provided in a wireless LAN where a fixed secret code or key known only to authorized users of the WLAN is used to restrict access to only those wireless devices that have the correct secret code or key available to them. This scheme is based on an RC4 encryption algorithm, has been compromised and is no longer considered to be a viable security solution.
2. WPA/802.1x based security solutions. This scheme was invented to overcome the shortcomings of WEP. This scheme involves dynamic keys and the authentication of the key each time a wireless device attempts to connect to the network. This scheme has also been compromised. There are several issues with Key management and weakness in the cryptography scheme. It has been shown that it is possible to decipher the secret key and gain unauthorized access to the wireless LAN. It is widely accepted that this method does not provide adequate security for a wireless LAN.
3. Virtual Private Networks (VPNs). This mechanism was adopted from the wired LAN side. Security is provided by creating virtual connections between wireless devices and their destination by virtue of encrypting the data transfer between them that is not decipherable by an unauthorized entity. This scheme works well in the wired LAN domain because the data is transmitted over a physical link such as a CAT5 cable. Unless someone can tap into that CAT5 cable, they cannot view the encrypted data stream. However, in the case of a wireless LAN, the data stream may be intercepted by a radio eavesdropper and potentially decoded. More importantly, it would be possible for a hostile entity to merely establish an ad-hoc connection with the authorized wireless device at one end of the virtual path and camouflage itself as if it were the authorized device itself. This is referred to as spoofing. It has been demonstrated that this type of security breach is possible.
4. Intrusion Detection Systems. These solutions rely on their ability to detect any radio frequency activity outside a known perimeter. As such, they are rendered ineffective by hostile entities that eavesdrop using a passive or listen-only mode and thus do not generate any radio frequency activity. It is widely accepted that this solution does not provide adequate security for wireless LANs.
5. Perimeter Control systems. These solutions depend on their ability to differentiate between authorized and unauthorized sources of radio transmission by measuring the relative signal strength of the radio frequency carrier signal. However, naturally occurring phenomenon such as multi-path signals may easily cause false alarms or camouflage unauthorized sources. In addition, passive eavesdropping is not detected by this solution. It is widely accepted that this solution is not ideal for providing a secure wireless LAN.
Thus the inability of any of these above approaches to restrict access to the radio waves carrying the Wireless LAN traffic renders them vulnerable to sophisticated radio frequency eavesdroppers and hence cannot be deemed secure. Accordingly, what is needed is a system and method to overcome these problems. The present invention addresses such a need.